1. Field of the Invention
The present invention relates generally to a surgical device, and, in particular, to a laser resectoscope for coagulating, cutting and removing prostatic and bladder tissue in a patient.
2. Description of the Prior Art
There are many methods for treating the obstructing prostate in male patients. These methods are medical and surgical. Since the beginning of this century the surgical approach was the only means of treating the prostate growth. The surgical approach was open prostate surgery, by cutting the skin and muscle to remove the obstructing prostate manually. The other approach was the use of a resectoscope. The resectoscope is an elongated sheath which is passed urethrally to the obstructing prostate. Electricity is then passed through a wire which is directed to remove the obstructing prostate in small chips. These small chips are initially thrown into the urinary bladder. At the end of the procedure, the prostatic chips are evacuated from the bladder and sent for pathological examination. It is estimated that at least 6% of these so called benign prostatic growths will be diagnosed as cancer of the prostate. Such cancer will eventually kill the patient if left untreated.
At the beginning of the 1980s, laser energy was used to burn the prostate using a procedure called ablation or vaporization of the prostate. In ablation prostate surgery, the entire prostate is burned beyond recognition, i.e. charred. Such a procedure has many disadvantages. Dead charred tissue is left behind to slough over many months, causing great discomfort to the patient. In addition, such dead tissue may cause of tissue scarring or infection. Both complications are difficult to treat. In addition, at least 6% of the prostate cancer is missed. No tissue diagnosis was possible using laser ablation procedure.
One alternative to laser ablation surgery is a procedure in which the prostate tissue is coagulated using laser energy. The laser used for this procedure is a Neodymium:Yttrium-Aluminum-Garnet (Nd:YAG) laser. The laser fiber is used in contact (or non contact) with the bladder or prostatic tissue to coagulate and cut the targeted tissue. Many companies manufacture Nd:YAG lasers. One company is LaserSonics located in Milpitas, California. In the past few years a YAG:Holmium laser was introduced. Coherent Medical Group of Palo Alto, Calif. manufactures the YAG:Holmium laser. The Holmium laser has an advantage of lesser tissue penetration than the Nd:YAG laser. Thus, more precise coagulation and cutting of the prostatic and bladder tissue is possible.
Many articles have been written using the Holmium:YAG laser. Using lasers to coagulate the prostatic or bladder tissue has a major advantage in that tissue architecture is preserved for pathological diagnosis. Unfortunately, no tissue diagnosis was attempted for many years. In 1988, the first description of coagulating the prostate and then removal was described in the literature. The advantage of such procedure was the removal of the dead coagulated prostatic tissue. Thus, less pain during voiding and less incidence of urinary tract infection is experienced by the patient. Retrieving the coagulated prostatic or bladder tissue will make it possible to diagnose prostate cancer in 6% or more of patients. Prostatic cancer in these patients was shown to advance and eventually kill the patient.
Laser energy falls within a small portion of the electromagnetic spectrum, and its wavelength is calculated in metric units. The wavelength of the Holmium laser is 2100 nanometers, while the Nd:YAG laser has a wavelength of 1064 nanometers; both of these lasers operate within the near infrared electromagnetic spectrum.
Lasers can cut, coagulate and ablate tissue, depending on the wavelength, power and frequency of the device. The optical fiber transmitting the laser energy can be used to remove or coagulate the tissue in either a contact or non-contact mode. In the contact mode, the optical fiber transmitting the laser energy is in physical contact with the tissue, while in the non-contact mode, the fiber is positioned between a few millimeters to a few centimeters away from the tissue. In this node, the laser energy travels through the liquid irrigating medium, such as saline solution, before contacting the tissue.
Thus, laser energy can be used to coagulate and cut tissue, in addition to the mechanical cutting means, which facilitates and accelerates the removal of the excised tissue. The tissue can then be submitted to a laboratory for pathological examination.
In addition, the removal of the dead coagulated prostatic or bladder tissue will result in early removal of the Foley urethral catheter which is inserted immediately after the use of the laser. The Foley catheter will divert the urine from the lased prostate or bladder tissue. The Foley catheter causes irritation and infection to the patient. The Foley catheter can be removed within hours of the laser surgery, unlike the use of diathermy electrical current in the conventional resectoscope, when the Foley catheter is left indwelling between 2-4 days.